Disappointed of this hope, some of the Helvetii endeavoured – generally, though not always, by night – to get across by lashing boats together and ma… - Gaius Julius Caesar

The Gauls’ own ships were built and rigged in a different manner from ours. They were made with much flatter bottoms, to help them to ride shallow water caused by shoals or ebb-tides. Exceptionally high bows and sterns fitted them for use in heavy seas and violent gales, and the hulls were made entirely of oak, to enable them to stand any amount of shocks and rough usage. The cross-timbers, which consisted of beams a foot wide, were fastened with iron bolts as thick as a man’s thumb. The anchors were secured with iron chains instead of ropes. They used sails made of raw hides or thin leather, either because they had no flax and were ignorant of its use, or more probably because they thought that ordinary sails would not stand the violent storms and squalls of the Atlantic and were not suitable for such heavy vessels. In meeting them the only advantage our ships possessed was that they were faster and could be propelled by oars; in other respects the enemy’s were much better adapted for sailing such treacherous and stormy waters. We could not injure them by ramming because they were so solidly built, and their height made it difficult to reach them with missiles or board them with grappling-irons. Moreover, when it began to blow hard and they were running before the wind, they weathered the storm more easily; they could bring in to shallow water with greater safety, and when left aground by the tide had nothing to fear from reefs or pointed rocks – whereas to our ships all these risks were formidable.

Accordingly tree trunks or very stout boughs were cut and their tops stripped of bark and sharpened; they were then fixed in long trenches dug five feet deep, with their lower ends made fast to one another to prevent their being pulled up and the branches projecting. There were five rows in each trench, touching one another and interlaced, and anyone who went among them was likely to impale himself on the sharp points. The soldiers called them boundary posts. In front of them, arranged in diagonal rows forming quincunxes, were pits three feet deep, tapering gradually towards the bottom, in which were embedded smooth logs as thick as a man’s thigh, with the ends sharpened and charred, and projecting only three inches above ground. To keep the logs firmly in position, earth was thrown into the pits and trodden down to a depth of one foot, the rest of the cavity being filled with twigs and brushwood to hide the trap. These were planted in groups, each containing eight rows three feet apart, and they were nicknamed lilies from their resemblance to that flower. In front of these again were blocks of wood a foot long with iron hooks fixed in them, called goads by the soldiers. These were sunk right into the ground and strewn thickly everywhere.

All bad precedents begin as justifiable measures.